Wow and I had enough trouble getting an AWS Org root account deleted (created by an employee who no longer works at the company). AWS sub orgs require you give the sub org a credit card, then close them independently.
Be sure to close the sub org first, then remove it from the root org. If you don't and don't have the root login for the sub account, you're going to have a bad time.
Be sure to close the sub org first, then remove it from the root org. If you don't and don't have the root login for the sub account, you're going to have a bad time.